Day: February 17, 2018

The problem with hanging on to old consumer products is that the original batteries no longer hold a charge. To make matters worse, replacement batteries ordered online have likely been sitting on a warehouse shelf for years and are no better. [Larry G] faced this issue with his old Nintendo DS Lite. Luckily he remembered a hack from his youth where a friend’s Dad had duct-taped a massive alkaline D-cell battery pack to the back of a Gameboy to give it a longer life. And so [Larry] gave new life to his Nintendo DS Lite by designing and 3D printing a case for a battery with an even larger capacity than the original.

He first obtained a 2400 mAh 18650 lithium-ion cell, one with over voltage and under voltage protection. With that as a guide, he designed and 3D printed a case for it made up of four printed parts. The case was needed because the 18650 doesn’t fit in the NDS Lite’s battery compartment. Instead, one of the parts, which he calls the fake battery, fits in the compartment and has copper strips glued to it for connecting to the NDS Lite. From there, wires go to another part wherein sits the 18650. The remaining parts secure it all in place. Charging is done using the NDS Lite’s built-in charger. Even though the new case adds significant bulk, it actually fits well in the hand.

No doubt many of you have your own old NDS Lite sitting around that can benefit from this repair. The project details and STL files can be found on his Hackaday.io page using the above link.

We’ve seen plenty of examples of neural networks listening to speech, reading characters, or identifying images. KickView had a different idea. They wanted to learn to recognize radio signals. Not just any radio signals, but Orthogonal Frequency Division Multiplexing (OFDM) waveforms.

OFDM is a modulation method used by WiFi, cable systems, and many other systems. In particular, they look at an 802.11g signal with a bandwidth of 20 MHz. The question is given a receiver for 802.11g, how can you reliably detect that an 802.11ac signal — up to 160 MHz — is using your channel? To demonstrate the technique they decided to detect 20 MHz signals using a 5 MHz bandwidth.

Fans of vintage codebreaking machinery might be interested to hear that the only working reconstruction of a Turing-Welchman Bombe is likely to soon be on the move. The electromechanical device, a replica of those used on the Second World War Enigma codes, is housed at Bletchley Park, the former codebreaking center established before the outbreak of war to house British and Polish codebreakers.

Bletchley Park itself is now a tourist attraction. The news is that a display reorganization has caused the Turing Welchman Bombe Rebuild Trust that owns the Bombe to approach the neighboring National Museum Of Computing with a view to housing it alongside their reconstruction of the Colossus electronic computer. The Colossus was famously used on the Lorenz cipher. This is an exciting development for the museum, but as an organization reliant on donations they face the task of finding the resources to create a new gallery for the arrival. To that end, they have launched a crowdfunding campaign with a target of £50000 ($69358.50), and they need your donations to it for the project to succeed. They have raised over £4500 in the few days it has already been open and there is most of a month still to go, so we hope they achieve their goal.

Running a classic car is often an easier prospect than a more recent model, as the mechanical parts have a tendency towards commonality between models, simplicity, and maintenance using basic tools. However assuming some level of parts availability for your model it is not usually the running gear that causes headaches. Instead, it is the smaller and less durable parts, the little plastic pieces that formed vital components but have not been manufactured for decades. These are the parts for which the advent of accessible 3D printing has been a revelation, suddenly the owner of a wreck need only to have basic CAD skills to deliver the goods.

A Chevy Corvair like [Ken’s]. Greg Gjerdingen [CC BY 2.0].[Ken] has a ’63 Chevy Corvair, an attractively-styled motor notable for its rear-engined layout and air-cooled engine. And it seems his car is plagued by the same issue as all other early models, a failure of its turn signal mechanism. The version fitted to later cars is a vastly superior replacement, but required some modification to fit his ’63 model. Even after modifcation, the updated part had a plastic component that was too long for his steering wheel. Would he grind down the later part to fit, or go with a later wheel? No, he turned to Google Sketchup, and 3D printed a replacement of the correct size. He does admit that it’s not perfect as the signals cancel at a slightly different point from where they should, but since he’s been using it for four years it appears to have done the job.

We wish [Ken] every success with his Corvair, and indeed can’t help envying him a little for owning it. Some of us have been known to dabble in older metal, too.

The twenty best projects will receive $100 in Tindie credit, and for the best projects by a Student or Organization, we’ve got two brand-new Prusa i3 MK3 printers. With a printer like that, you’ll be breaking stuff around the house just to have an excuse to make replacement parts.

If you were building a recreation of the James Watt micrometer, where would you start? If you’re [rasp], the answer would be: “Spend a year trying to find the best way to make etched brass discs.” Luckily for us, he’s ready to share that information with the rest of the world. While it’s rather unlikely anyone else is working on this specific project, the methods he details for getting museum-quality results on brass are absolutely fascinating.

The process starts with sanding down the bare brass and applying a layer of clear packing tape to the metal. [rasp] then covers the piece with LaserTape, which is a special tape designed to make laser-cut masks for sandblasting. But the masking principle works just as well for painting or chemical etching.

With the LaserTape in place, the piece is then put into the laser and the mask is cut out. Once cut, there’s the tedious task of peeling off all the cut pieces of tape, which [rasp] does with a dental pick. Once the pieces are pulled off, the brass is ready for its acid bath.

Anyone who’s etched their own PCB with ferric chloride will recognize these next steps. The piece is put into the acid bath and agitated every 10 minutes or so. It’s interesting to note that [rasp] places the piece in the bath upside-down, using little 3D printed “feet” to suspend the brass sheet off the bottom of the container. This allows the debris from the etching process to fall down and away from the piece. After about an hour out in the sun, the piece is pulled out of the bath and carefully washed off.

Once clean off, the piece is sprayed with black spray paint to darken up the etched areas. The moment of truth comes when the paint has dried and the layers of tape are carefully peeled back to reveal the etching. [rasp] then wet sands the piece with 1000 and 2000 grit paper, and a final pass with polishing compound brighten up the surface to a mirror-like shine. It’s quite a bit of manual labor, but the end result really is spectacular.

In the video after the break, [rasp] breaks down the entire process, including the additional machine work required to turn these brass plates into functional components of the final machine. As an added bonus, he even includes a lot of his failed attempts in an effort to keep others from making the same mistakes. Something we love to see here at Hackaday.

The pitch to my wife was simple: “Feel like spending the weekend in Seattle?” That’s how I ended up at the inaugural Vintage Computer Festival Pacific Northwest last weekend, and I’m glad we made the five-hour drive into The Big City to check it out. Hackaday is a VCF sponsor, after all, so it seemed like a great excuse to make the trip. That it ended up being two consecutive days of great Seattle weather was only icing on the cake of being able to spend time with fellow retro computer aficionados and their dearest bits of old hardware, in a great museum dedicated to keeping computer history alive and accessible.

The fact that Seattle, home of Microsoft, Amazon, and dozens of other tech companies, has until now been left out of the loop in favor of VCF East in New Jersey and VCF West in Mountain View seems strange, but judging by the reception, VCF PNW is here to stay and poised to grow. There were 20 exhibitors for this go around, showing off everything from reanimated PDP-11 and Altair 8800 control panels to TRS-80s from Model 1 through to the CoCo. Almost every class of reasonably transportable retro hardware was represented, as well as some that pushed the portability envelope, like a working PDP-8 and a huge Symbolics 3640 LISP workstation.

[MeasuredWorkshop] wanted to know how a boxing bell mechanism worked. The best way to learn is by doing, so he jumped right in and built one! Boxing bells are a rare surviving example of the trip bell mechanism. Trip bells were used in schools and public buildings as fire alarms. They’ve since been replaced by modern electric systems.

The mechanical linkage behind the trip bell is a one-way lever. This is the arm you pull on. It has a hinged section which stays rigid when the arm is pulled down, but rotates away when the arm is released. [Measured Workshop] built the mechanics of his bell using rather basic tools. The brunt of the work was handled by an angle grinder and a drill press.

The sounder for this boxing bell came from an old school bell. The industrial grey paint was chemically stripped, and the metal cleaned up for a nice brushed finish. The metal stands out nicely against the wood board [Measured Workshop] used as a base.

The finished product looks and sounds the part – now he just has to find a boxing gym in need of a bell!